This invention relates to an optimized display device memory utilization method.
A conventional display device has comprised an indicating memory device including a parallel combination of a red, a green and a blue memory connected between an address changing circuit and a display indicating device of the raster scan type. The address changing circuit selects address lines within an indication control circuit connected thereto so that the indication control circuit applies successively and simultaneously indicating addresses to all the red, green and blue memories through the address changing circuit and in synchronism with a scanning signal applied to the display indicating device. The red, green and blue memories are successively responsive to the indicating addresses applied thereto to supply successively red, green and blue pieces of color information stored at corresponding addresses thereof to the display indicating device at associated addresses. This has resulted in an indication of a color image on the display indicating device as determined by the red, green and blue pieces of color information stored in the red, green and blue memories at the respective addresses.
When a color image is not displayed on the display indicating device, the address changing circuit selects address lines within a central processing unit connected thereto to cause the latter to read out and write data from and into the red, green and blue memories through the address changing circuit.
In conventional display devices such as described above, it has been necessary to always use the red, green, and blue memories and to also increase the storage capacity of the memories in accordance with the particular dot resolution when an increased dot resolution is desired while decreasing an associated color resolution during the indication of characters. The term "dot resolution" used herein and in the appended claims is defined as the degree to which the brilliance of a dot can be discriminated and the term "color resolution" is similarly defined as the degree to which a color can be discriminated as to its hue, saturation and brilliance. Furthermore, when it is necessary for the display indicating device to display a figure mixed with characters in a single picture, a disadvantage has resulted in that the color information memories which have been prepared for an associated character section are wasted.
Accordingly, it is an object of the present invention to provide a new and improved optimized display device memory device method, wherein the display device is arranged to increase its dot resolution upon displaying characters while increasing its color resolution upon displaying a figure.